At the pie graphic you will see the labels have encoding issues, but they are there, could this be the reason for canvas not showing labels, my data is in utf-8 and words have accents…

CanvasJS doesn’t have any issue rendering Accented Characters. Problem is that JSON that you are generating doesn’t have label values set – labels are null in case of 2nd, 3rd and 4th chart’s JSON data.

Given that JSON data of first chart has labels set properly, you can compare that code with that of 2nd chart’s JSON generating code (on the server side).